One common type of tie rod utilized for supporting the forms used in pouring concrete walls is a break back tie rod which is manufactured with weakened sections which permit the rod to be broken off a short distance inwardly of both faces of the wall when the wall forms are removed. A section of the tie rod, therefore, remains embedded in the wall and the openings extending from the broken ends of the tie rod to the faces of the wall are usually sealed with grout or the like.
In a more recently developed form of tie rod, as shown, for example, in U.S. Pat. No. 3,437,309, the tie rod is surrounded by a sleeve which allows the tie rod to be removed from a wall and reused, resulting not only in a savings in material costs, but also requiring less labor for tie rod removal.
However, the reusable type of tie rod results in an opening extending completely through the wall, which not only may be considered aesthetically undesirable, but results in an unacceptable construction where the function of the wall requires that it be imperforate as, for example, where it forms a barrier against water. In this regard, it should be noted that substantial hydrostatic pressure may often be encountered acting against the face of the wall.
While conventional practice is to attempt to grout the tie rod openings formed through a wall, this is obviously an expensive method and often results in an unacceptable seal, due in part at least to the normal shrinkage associated with the curing of the grout after it has been placed into the tie rod hole.
One solution to this problem has been proposed in U.S. Pat. No. 3,390,498, wherein a polyethylene plug is disclosed which is adapted to be packed into a tie rod hole, the outer surface of the plug having circumferential ribs for anchoring the plug in place and preventing water seepage through the hole.